In this mid-career patient-oriented research application, the candidate, Dr. Seward Rutkove, proposes to pursue his long-term career goal of improving the assessment techniques used in the evaluation of patients with neuromuscular disorders and mentoring promising new investigators in neuromuscular disease research. Over the past 8 years, his major research effort has been in the development of the new technique of electrical impedance myography (EIM). EIM is a non-invasive, painless, approach to assessing muscle through the surface application and measurement of high-frequency, low-intensity electrical current. His research group has been pursuing the development of this technique through 3 separate short-term goals all of which have been grant supported: 1) the development of improved EIM electronics/engineering; 2) the development of an improved understanding of EIM theory; and 3) the clinical application, technology transfer, and dissemination of this technique. The environment supporting this work is rich and includes the Department of Neurology at Harvard Medical School/Beth Israel Deaconess Medical Center, where Dr. Rutkove is based. Dr. Rutkove has also established collaborations with engineers at Massachusetts Institute of Technology and physicists at Northeastern University, who have been assisting in device refinement and EIM theory development, respectively. In addition, this environment is especially conducive to the mentoring of new clinical investigators, with Dr. Rutkove already having substantial experience as a mentor. The research plan focuses on the blinded, prospective assessment of EIM versus EMG for use in the evaluation of two extremely common neuromuscular disorders: cervical and lumbosacral radiculopathy. The ultimate goal of this project is that of achieving Class I evidence supporting the value of the technique in the diagnosis of these neuromuscular conditions. The specific aims of the plan include: 1) A prospective, blinded evaluation of EIM and EMG in the diagnosis of cervical and lumbosacral radiculopathy; 2) a prospective, blinded evaluation of EIM and EMG in the evaluation of radiculopathy severity; 3. a prospective, blinded comparison of EIM and EMG in assessing the acuteness/chronicity of radiculopathy. A rich, structured, mentoring plan is also provided, including the expectation that young investigator's take ownership of individual projects during their training with Dr. Rutkove. Should this research prove EIM to be an effective test for the initial assessment of radiculopathy, the requirement for the painful, invasive test of needle EMG will be substantially reduced or possibly eliminated. This would lead to improved assessment and care for individuals suffering from this very common malady. Regardless of the specific success of EIM, a group of young investigators will be thoroughly trained to pursue patient-oriented neuromuscular disease research.